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Test Code TPI1 Triosephosphate Isomerase Enzyme Activity, Blood


Specimen Required


Container/Tube:

Preferred: Yellow top (ACD solution B)

Acceptable: Lavender top (EDTA)

Specimen Volume: 6 mL

Collection Instructions: Send in original tube. Do not transfer blood to other containers.


Secondary ID

607458

Useful For

Evaluating individuals with chronic nonspherocytic hemolytic anemia

 

Evaluating individuals with early onset neurologic impairment

 

Genetic counseling for families with triosephosphate isomerase deficiency

Method Name

Kinetic Spectrophotometry (KS)

Reporting Name

Triosephosphate Isomerase, B

Specimen Type

Whole Blood ACD-B

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood ACD-B Refrigerated 20 days

Reject Due To

Gross hemolysis Reject

Clinical Information

Triosephosphate isomerase (TPI) converts dihydroxyacetone phosphate to glyceraldehyde 3-phosphate during glycolysis. Clinically significant TPI deficiency (OMIM #615512, autosomal recessive) is rare and classically manifests as a severe multisystem disorder with early hemolytic anemia and progressive neurologic impairment in infancy. Other clinical features include motor impairment, diaphragm paralysis, cardiomyopathy, and susceptibility to infections. Some cases have isolated hemolytic anemia.

Reference Values

≥12 months: 1033-1363 U/g Hb

Reference values have not been established for patients who are less than12 months of age.

Interpretation

Clinically significant hemolytic anemias due to triosephosphate isomerase deficiency are associated with activity levels below 30% of mean normal. Heterozygotes usually show approximately 50% of mean normal activity and are clinically unaffected.

Specimen Retention Time

7 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TPI1 Triosephosphate Isomerase, B 44054-5

 

Result ID Test Result Name Result LOINC Value
TPICL Triosephosphate Isomerase, B 44054-5

Day(s) Performed

Tuesday, Thursday

Report Available

1 to 6 days

Forms

If not ordering electronically, complete, print, and send a Benign Hematology Test Request (T755) with the specimen.